Catalytic discrimination between inequivalent formyl groups was achieved using an aniline-type acid–base catalyst for the regio-, diastereo-, and enantioselective intramolecular cross-aldol reactions of enolizable dials. Although L-proline gave a mixture of the regio- and stereoisomeric products in the presence of an N-containing 1,6-dial, the aniline-type catalyst afforded anti-3,4-disubstituted pyrrolidine